Manufacture of metal nitrogen compounds.



LICKFE 'IT, 0F RJUKAN', TELEMARKEN, NORWAY, ASSINOIEtS TO THE,

RICHARD GREU'LICI-I, 0F LUDWIGSHAFEN-QZtl-1LHE-RHINE, GERMANY, AND HERBERT sensuous stutter, e. n. :e. n, on LUDWIG$H7AFEN$N-THE-RHINR onnzuan MANUFACTURE 0F METAL NITRllGEH GOMPOUNDS.

1 EfiSJZlli.

1% Drawing.

To all whom it may concern Be it known that we, RIGHARD Gnnumon, chemist, a subject of the King of Saxony and the German Emperor, and HERBERT Lrcnrnr'r, chemist, a subject of the King of Prussia and the German Emperor, residing at Ludwigshafen on 5 the Rhine, Bayernstrasse 34L, Kingdom oi? Bavaria, German Empire, and Rjukan, Telemarken, Kingdom of Norway, respectively, have inventeda new and useful Improvement in the Manufacture of Metal Nitrogen Compounds; and We do hereby declare the following to he a full, clear, and exact description of the same.

.lt is known thatin the production of aluminium nitrid by heating a mixture of alumina and carbon in the presence of nitrogen, the temperature of formation can be lowered by the addition" of a basic metal oxid, or hydroxid, such as lime, baryta and thediire or by the addition of salts of such metals. In practice it has however been found that the amount which can be used of such additional substance is too small to accelerate, or facilitate, to any marked clegree, the formation of the nitrid and, even witlnirom 2 to 6 per cent. of the additional substance, great diiiiculties arise in the practical carrying out of the process, as the mixture sinters and melts and the Walls of the vessels are highlyattacked and the nitro gen does not obtain proper contact with the sintered, or molten, mass, and, the yield of aluminium nitricl is very small.

These objections are greater when, in

order to accelerate the reaction, larger amounts of the additional substance are used as thenv the mass fuses and forms a solid slag and entirely prevents the passage of the nitrogen, so that practically no nitrid is formed.

It has been proposed to prevent, or reduce, this slaggin in various Ways; for instance, in the specification '1 Serpeks German Patout No. 235,669, it is proposed to first hea t a mixture of 49 parts of alumina, 4 parts of baryta and 12 parts of carbon Without supplying nitrogen and then to powder tlfe I This process cooled slag thus; produced and then in a second operation to heat the powdered slag in a current oi nitrogen together With alumina.

practice, as, owing to the slaggiug of" the Specification of Letters Patent.

Application filed. November 28,1913. Serial No. 808,572.

presents great dificulties in Patented June a,

product, the walls of the vessels are highly attacked, and injured and the division of the process into two phases causes Waste of time and is expensive and the process cannot be carried oncontinuously.

It has been proposed to overcome the jections by adding a large excess of carbon,

and it is possible to decrease the slugging by the use for instance of a quantity of carhon ,in excess equal to twenty times the quantity theoretically required but the prodnot obtained is contaminated with a, consideralile amount of carbid and carbon which is not suitable to a manufacture of alumina,

etc, and further, the process is not economi cal, as an enormous amount of carbon is heated uselessly Without increasing the yield of nit-rid.

We have found that it is possible to successfully use, in the manufacture of metal nitrogen compounds as nitrids,-tfor instance aluminium nitrid/large amounts or" adclitional substances, such as a basic metal oxid, or hydroxid, or a salt, for accelerating the reaction, so as to control and regulate the velocity of reaction according to requirements nnd to avoid slugging and thereby allow the absorption of nitrogen to he uni form and cause the vessels to last longer, if a mixture of alumina, or alumina-containing substance and carbon with any desred amount of metal oxid or the like, be heated in a vessel (such for instance as a tube) which is formed of carbon, or which is pro vided internally with a covering or coating or lining of carbon, as then not only will the walls of the vessel be protected but coalescing and slugging together of the sub stances employed will he prevented.

This invention in contradistinction to the known processes enables the amount of the metal oxidmuother additional substance, to be added to the mixture of alumina and carbon, to he varied as desired so that the greatest amount of such additional substance desined'can be used to accelerate the reaction while no melting of the mass occurs, it

remaining so porous as to allntv the proper passage of the'nitrogen through the mass.

' In consequence the yield of aluminium nitrid condition better treatment. (hiring of the particles of ma- IJ siderably lowers the temperature of :l'orinatron of the nitricl, Which is obtained in a adapted for subsequent teri'al together and adherence to the valls of the vessel are prevented also when coarse p1eces of materlal are employed.

We have found that a vessel, or tube, with w an inner surface 01"- carbon or such a tube of carbonespecially if it is as pure as posslbl'e (such for instance as the carbon used for electrodes) is not chemically attacked,

or destroyed, by the incandescent mass therein. The presence of mud of iron, trtanluln, silicon, or similar matters which may occur in the initial material, such, for

instance Na,CO,,, li,OO;,, (latltl Baliifh) and the mixture is placed in a vessel such as a retort, or tube, or the like of refractory material, 101 example burnt hrc clay, which is'heated from the outside while nitrogen is passed through. The inner wall of the said 'vessel, tube, or the like, is coated entirely,

or only along the firing zone, with a. layer of carbon such as graphite, or the like. .l or example such a coating of firnily adherent graphite can-be readilyo'btained by raising acoal to incandesccnce in the vessel, tube, or .the l1ke,'of refractory material from which air is excluded. In this way a firm coating of carboilis deposited on the innerwall of the vessel, tube, or the like. Instead oi coating the vessel, tube, or the like, With a layer of graphite or other form of carbon, vessels, tubes, or the like, of burnt lire-clay may be provided with an inner tube of coal, or other form of carbon which, for prevent ing loss of heat, should it as closely as 1 .'ac-

.ticable, the outer vessel, tube, or the like.

M is advantageous to carry out the n'ocess 111 a continuous manner, by su jiplying the m n ature of alumina, carbon, and. any suit "able large proportion of additional substance and the nitrogen to the vessel, tube,

orthe like, having an interior of carbon the mtrid formed. being tapped oil hr'om below. Frorntne foregoing description it 'Wlll be readily understood that the invention can be siirnilarly applied to the manufacture of nitrids other than aluminium .i'iitri'd and also to the manufacture of cyanide and the like by suitable selection of the initial materials.

It'has been propos'sed for heating mixtures of aluminous material and carbon, but without additions facilitating the absorption of nitrogen, to use carbon tubes as conductors for electricity, in order to vaporize the inipurities present in the alulninous material, especiallysilioa, alkaline earths and alkalis, for which high temperatures available by electricity, The pl sent invention refers ere clusi'vely to the manufacture of nitrids by means of mixtures oi? the initial material, carbon and any suitable large proportion of additions facilitating theabsofption of nitrogen. leaving out of account the small of iin 'iurities being; contained in the initial mat The use of such mixtu eon also proposed, but not in cone buiation n th carbon vessels. la e'do not claim the said icatiu'es' separatelybut only the combinahon of the two features.

Having now particularly described and ascertained the nature of our said. invention, and in What manner the same is to be performed, We declare that whatwe claim is- 1. 1n the man'ulaotiue of nitrogen 00111- pounds of metals, the step which consists in heating a mixture of conuiounds of the metal with substances accelerating the absorption of nitrogen thereby, in a carbon lined vessel, in the presence of nitrogenous gases, and to a temperature below the sintering temperature of the mixture.

:2. In the inanuflhcture of nitrogen coinpounds of metals in a carbon lined vessel, mining the initial compound of the metal with such amount, of substances accelerating the absorption of nitrogen that a deleterious slugging would result the retort were not carbon lined; conducting the mixture into such. a vessel; and heating the mixture While therein, by exteriorly heating said vessel, to a ton'iperatin'e below the sintering temperature of the iniuturaainl in the presence of nitrogenous gases.

in. testi .iozuy wl'iereof, We have signed our names to this spccilimition in the presence of two subscribing witnesses.

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